This invention relates to a quick connector with a through bore in its connected position, comprising two main parts, each formed to be screwed to a pipe-/socket-shaped connecting portion of respectively a pipe, preferably coiled tubing, and a tool or other equipment therefor, wherein a first main part comprises a conical pin element narrowing towards its free end, whereas a second main part comprises a pin-accommodating bore of an essentially complementary conical extent.
Such a connector is suitable for use in connection with pipes and tools with a threaded socket, for example for connecting a tool to the end of coiled tubing. Of the two sleeve-shaped connecting elements of the connector, one can be coaxially inserted into/extracted from the other, and the engagement established can be secured by a releasable locking device.
When coiled tubing is in use, it is provided with a tool at its free end, for example an impact tool. In their inoperative condition, the tools are suspended by means of slips in the drill floor, for example.
With a desired tool in the suspended position, the coiled tubing is run out from its drum by means of an injector arranged thereto, for the connection of the suspended tool. The end of the coiled tubing is formed with external threads for screwing to an internally threaded socket-like connecting portion of the tool.
Coiled tubing are relatively rigid and buckled, which is due partly to their tendency of plastic deformation when bended in particular ways, and it is often very difficult to make the externally threaded portion of coiled tubing enter the internally threaded bore of the connecting portion of the tool with the mutually adapted threads in engagement. Therefore, the big and heavy tool mostly has to be oriented and adapted to the connecting end of the coiled tubing, which may adopt a mainly stationary position, as the tool is rotated manually for its connecting portion to be connected to the end of coiled tubing.
This operation of screwing together is work which is carried out manually, and which is often very time-consuming because it is an invariable requirement that the cooperating threads engage each other with precision.
German publication No. 1 066 515 discloses a drill string pipe, which has, at its connecting end portion above another drill string pipe, a socket which has, in the longitudinal direction of the pipe, a first portion in which the socket bore widens conically towards its free end, which internal, conical portion ends at a distance from the free end of the socket. Between the conical portion and the free end of the socket is formed a circular-cylindrical intermediate portion. The second pipe which is to be connected by its end adjacent to the socket of the former drill string pipe, has a pin element, whose external surface is essentially complementarily corresponding to the internal surface portions of the connector sleeve. The conical portion of the pin element narrows towards, and extends to, the free end thereof, and this portion is positioned in the internal conically extending region of the socket. In the upper internal circular-cylindrical portion of the socket, in whose region the correspondingly formed portion of the pin element is located in the position of connection, there are formed axially directed grooves, which are engaged, in a longitudinally displaceable manner, by teeth of a gear rim fixed externally on the pin element. A lock mandrel secures the engagement of the pin element in the bore of the socket, and is firmly screwed to the exterior of the socket, which has for this purpose external threads in the region of the circular-cylindrical portions of the socket and pin element. This lock mandrel is relatively complicated and cooperates with an external flange on the pin element. This known connector is not pressure-tight, and thus unsuitable in oil drilling. The teeth of the gear rim and the axially directed grooves engaged in an axially displaceable manner by the straight teeth are not formed on the conical portions of the cooperating connector parts (the inside of the socket, the outside of the pin element), and teeth and grooves are not particularly elongate.
According to the invention, is to be possible for a pipe-shaped threaded end of, for example, coiled tubing to be connected to any tool by an intermediate quick connector, whose one threaded main part is formed to be screwed to the threaded end of coiled tubing, whereas its other threaded main part is formed to be screwed to a tool of a complementarily threaded connecting portion, said two main parts being connectable to one another.
It is a simple matter to connect one main part of the connector by screwing to the end of coiled tubing, because this main part which is light in weight and fit for manual handling compared to the complete tool, may easily be oriented and positioned relative to the end of coiled tubing, which end often adopts, due to its stiffness and lack of flexibility, a stationary position during the screwing together, and similarly, the screwing together of the other main part of the connector and the threaded connecting portion of the tool represents an easy operation. Then it remains to connect said two main parts of the connector, and it is the simplification and improvement of the screwing together of the main parts of the connector that has been the aim of the present invention.
The connectable main parts of the connector, which are concentric in the connected condition of the connector, are formed so that by a pin-shaped portion one main part coaxially engages a bore which is formed in the other main part, said pin-shaped insert portion being formed narrowing in the direction towards its free end, the internal wall surface defining the pin-accommodating bore of the other main part being formed with an essentially complementary extent. Each main part is formed with cooperating longitudinal elongate, axial, ridges distributed circumferentially with intermediate channel-shaped grooves, the axially directed ridges of one main part having a rounding at the top of the ridges.
These rounded portions of the elongate axially directed ridges, and possibly of the channel-shaped bottoms of the intermediate grooves, ensure a precise guiding in the insertion of the pin element into the bore defined by internal ridges and intermediate grooves.
The first portion of the conically narrowing pin element of the one main part, inserted into the bore defined by an internal conical wall surface, will, due to its conicity, not be in any but random contact with the ridges projecting radially inwards, so that normally the pin element will have entered some distance into said bore before its elongate axially directed ridges obtain a guiding contact with the ridges/grooves of the bore-defining internal wall, for the ridges of one part to be guided into the grooves of the other part, so that finally an engagement has been established like between axial sliding grooves. Such an engagement is not effective from the moment when the two conical engagement means reach coaxial positions, as the engagementxe2x80x94the ridges of one part engaging the grooves of the other part and vice versaxe2x80x94is established only at a somewhat later point, and the roundings at the top portions of the ridges, and possibly at the bottom portions of the grooves, ensure, during the successive insertion of the pin element into the bore, that a precisely guided insertion takes place, so that this engagement is established smoothly and reliably, without the risk of the parts jamming before the desired final position has been reached.
This ideal engagement of said ridges and intermediate grooves may be secured by a suitable locking device, for example in the form of a lock mandrel with internal threads at one axial portion cooperating with external threads of one of the main parts, the lock mandrel being formed at its opposite axial end portion to enclose a split expansion ring, which engages, by internal projections, external grooves of the cylindrical portion of the other main part.
The connector is to be pressure-tight, and is therefore provided with two seal rings positioned near one another in the area between the free end portion of the pin element and the surrounding internal wall surface portion defining the bore of the other main part of the connector at this point.
The simplified, improved connection of a suspended tool to an end of coiled tubing by means of the interconnected connector according to the invention is caused by the combination of the conical cooperating engaging elements and the rounding of said elongate, circumferentially distributed, axially directed grooves and possibly intermediate grooves at the ridge top portions and groove bottom portions. Through a combined effect these two features of the invention facilitate and control the accurate centric insertion of said pin element of one main part into the pin-accommodating bore of the other main part, until a complete engagement has been established evenly in the circumferential direction and in a considerable longitudinal extent axially, in which the connector may be secured in the suggested way or in a technically equivalent way.
Especially in the pin-accommodating bore of one main part of the connector, the ridges may have, at their free ends, a portion smoothly merging with a cylindrical portion, which has no ridges. The ridges defining, together with the intermediate grooves, the pin-accommodating bore may have similar sloping transition surfaces at their upper axial ends.
Further objectives, advantages and features of the present invention will appear from the following specification referring to a non-limiting example of a preferred embodiment.